[Enhancement] Add songs in platform playlist when added to Grüvee playlist

[adilanchian]

Is your feature request related to a problem? Please describe.
Currently, we have the ability to setup a playlist on behalf of the user in their platform of choice when they login. The only thing we are not doing is adding anymore media to it once it's created. For example, if I add a song to my Grüvee playlist, I would expect my Spotify playlist to also update properly.

Describe the solution you'd like
The way this will end up working is as follows:

1. Add media to Grüvee playlist
2. New song document is created for newly added song
3. FetchAllMedia Firebase function is fired off which gets song data for all other platforms
4. On client check to see if user has API token available for writing to a playlist
5. If so, we will be creating a new firebase function to go off to the platform and add the song

One big thing that will be setup here as well is if we are adding a playlist or an album, we need to traverse through all the tracks and them to the playlist separately.